This is one of five studies performed in 1976 to examine the characteristics of U.S. medical schools and the interrelationship among variables that describe them. A principal components analysis was performed and interpreted exploring the interrelationships of 33 selected variables that describe the faculty, student, curriculum, and other institutional characteristics of medical schools. A summary of the concepts underlying principal components analysis is presented, and the resulting factor pattern is presented and interpreted. Several speculative observations were made based solely on correlations in the data, and are suggested hypotheses for further analysis: (1) schools with an emphasis on graduate medical programs have proportionally fewer MD-program alumni going into general practice; (2) larger and older schools have proportionally more alumni receiving board certification; (3) private schools receive greater proportions of their revenue from gifts and federal sources; (4) schools with greater proportions of female students have a greater rate of approval of their NIH research grant proposals; (5) schools that have receieved larger increases in research funding between l967 and l974 tend to be the schools that anticipate the most growth in enrollment in the next five years; and (6) schools receiving the most research grants and expending the larger proportions of their budgets for sponsored research expend smaller proportions of their budgets for administration and general expense. (Author/MSE)